Eight million Americans rely on Synthroid to regulate an overactive or underactive thyroid, but the US Food and Drug Administration (FDA) is concerned that patients may not be getting the dose their doctors prescribe. CBS 2's Paul Moniz reports.
Synthroid, the nation's third most popular drug, is a mainstay of thyroid treatment. More than 43 million prescriptions were written last year to patients like Amy Martin who cope with potentially debilitating symptoms of thyroid hormone imbalance.
"I'm still exhausted, struggle to concentrate, at the point I'm really desperate," says Martin.
But the FDA now says Abbott Labs, the manufacturer of Synthroid, has not proven the drug is safe and effective. The FDA confirms an article in the Wall Street Journal saying the agency is considering pulling Synthroid off the market.
In a letter to Abbott, the FDA says evidence it has obtained "suggests a long history of manufacturing problems," concluding that Synthroid has stability, potency, and consistency problems and may be "neither safe nor effective."
Patient advocates complain because patients can't be guaranteed a consistent dose from refill to refill and many report a fluctuation in symptoms, including going into hypothyroidism and having heart palpitation or anxiety symptoms. And if they get a sub-potent batch they could find themselves gaining weight.
Endocrinologist Stanley Goldsmith, however, is skeptical of those reports. He says his experience with Synthroid has been positive.
"It's convenient to use, patients know it, and we have a lot of confidence in it," says Goldsmith. "I have relatives that I prescribe this to."
Since Synthroid is a 40-year-old drug, it has never even been formally approved by the FDA.
In 1997, after reports of adverse reactions, the FDA informed all manufacturers making this class of drug that they needed FDA approval to continue marketing their product. Two of Synthroid's competitors did and have been approved, but Abbott has not submitted the material.
Dr. Goldsmith stresses that patients should not panic, especially if Synthroid is working for them.
"The take-home message is to stay calm," says Goldsmith. "I would hope the company would be responsible and come forward with data that really puts this to rest."
After repeated phone calls, a representative from Abbott Labs now says the company will file a new drug application with the FDA before the August 14 deadline.
The company had filed a "citizen's petition" to get Synthroid classified as "generally safe and effective" because its been around for so long. But last month the FDA rejected that request demanding the full review.
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